1. Field of the Invention
The present invention relates to a mobile communication system, a wireless base station control device and an operation control method that apply a plurality types of networks.
2. Description of the Related Art
In recent years, the W-CDMA (Wideband-Code Division Multiple Access) method has become rapidly widespread for use in mobile communication systems.
FIG. 1 shows a mobile communication system using a conventional W-CDMA method that includes CN (Core Network) 1001, RAN (Radio Access Network) 1002 and UE (User Equipment) 1003. CN 1001 is a core network that provides a circuit-switching service or a packet-switching service. RAN 1002 is a wireless access network that is connected with CN 1001 via an Iu interface. UE 1003 is a mobile device owned by a user, connected with RAN 1002 via a Uu interface.
RAN 1002 further includes RNCs (Radio Network Controllers) 1004 and 1005 and Node Bs 1006 to 1009. RNCs 1004 and 1005 are wireless base station control devices that control Node Bs 1006 to 1009 and are connected to Node Bs 1006 to 1009 via an Iub interface. Node Bs 1006 to 1009 are wireless base stations for covering one or more cells. The number of RNCs 1004 and 1005 and the number of Node Bs 1006 to 1009 are not limited to those shown in FIG. 1.
The ATM network and the IP network are considered as examples of networks applied as RAN 1002, which is a wireless access network here. The wireless network control device that can address those networks is disclosed in WO2004-028098A.
The ATM network, which has been widely used as the RAN, is a network effective for transferring not only a circuit-switching service but also a packet-switching service and has functions for managing traffic and controlling the quality for traffic having various characteristics. To cover a wide range of RAN, a sufficient number of ATM lines needs to be laid. That leads to the problem that in introducing and operating the network, costs will increase.
On the other hand, the IP network, which has been newly added with Re1.5 specification of the 3GPP (3rd Generation Partnership Project), can lower the cost of introducing and operating the network as compared with the ATM network because fixed-networks have been significantly developed worldwide. However, the IP network has a problem in that it is not appropriate for transferring control information or a circuit-switching service because the transmission delays in this network are large.
The method described in WO2004-028098A does not include a flexible method for selecting between the ATM network and the IP network according to their conditions.